


The Reason (Is You)

by MarbleHeart



Category: Doctor Who (2005)
Genre: Because I can't help myself and also how do you avoid it completely with these two, But it is very light though, Declarations Of Love, F/F, Fluff, Happy Ending, Kissing, Light Angst, Reunions, Reunited and It Feels So Good
Language: English
Status: Completed
Published: 2019-09-19
Updated: 2019-09-19
Packaged: 2020-10-24 07:06:45
Rating: General Audiences
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 4,518
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/20701922
Author URL: https://archiveofourown.org/users/MarbleHeart/pseuds/MarbleHeart
Summary: There had been a reason he'd turned young, in the first place. He'd felt so old, after the war. There had been a reason he'd gone Scottish. Definitely had to do with the mark left on him by a person he would've quite confidently called his best friend, that certain feisty redhead he'd met in a back garden. And now... there was a reason he had become she, and there was a reason that she was blonde. That reason had a name; Rose Tyler.





	The Reason (Is You)

**Author's Note:**

> Basically, I'm gay as hell, and when I read that Billie Piper said she thinks Rose would still be in love with The Thirteenth Doctor I just. Lost my mind. Needed to write something of them. The Doctor/Rose is one of my fave ships of all time tbh. Took me quite a while to get around to it, but I hope this quick and feelsy fluff is enjoyable! :)  
And yes, if you're wondering, I heard 'The Reason' by Hoobastank on the radio the other day, and it got my cogs spinning on this because I'm old and, as previously mentioned, gay as hell.

There had been a reason he'd turned young, in the first place. He'd felt so old, after the war. There had been a reason he'd gone Scottish. Definitely had to do with the mark left on him by a person he would've quite confidently called his best friend, that certain feisty redhead he'd met in a back garden. And now... there was a reason _he_ had become _she_, and there was a reason that she was _blonde_. That reason had a name; Rose Tyler.  
  
There was at least _some_ identifiable pattern to the regenerations. It seemed that it had to do with who or what The Doctor had been thinking about at the time. She'd figured it out at some point while she was still wearing her previous face. That fact had been especially fortuitous, since when that face had first appeared, the subject of where it had come from had been quite an obsession.  
  
But by this point she understood. She'd been thinking of Amy, and gone Scottish. She'd needed to send herself a message, so had ended up with the face of someone she'd protected. To remind herself that she saved people. Assistance with the impending morality crisis she'd been about to have.  
  
So, when she'd looked into a mirror for the first time after this last change, immediately she knew why she looked the way she had. She hadn't realized she'd been thinking of Rose... but perhaps, in the back of her mind, she was _always_ thinking of Rose.  
  
Thinking of Rose had also brought her back to Bad Wolf Bay, apparently. She told the TARDIS to just take her somewhere, and it seemed to know just where she needed to go, even if she herself hadn't.  
  
When the door opened, she balked slightly. She could recognize the beach before the details even had time to register. "Oi, you're kidding me." She said, turning back toward the console, which seemed to flash at her with a mixture of amusement and benevolence.  
  
She hadn't given it the time of day to even think it might be _possible_ to come here again.  
  
It might've been a mental block more than anything else, though. She was standing here, sure enough. Evidently it was still _very_ possible for her to get into this universe. Perhaps even more so, now that she'd found Gallifrey. A lot of things had changed since the last time she'd seen Rose Tyler.  
  
She twisted around again, following the sound of the waves and the scent of the salt they carried. Well, what was the harm? Rose wouldn't recognize her. She wouldn't be scanning the crowds for a _woman_. Who knew if she'd even be scanning the crowds for those pinstripes and sideburns anymore. She wouldn't, if things had gone according to plan. She had those sideburns right beside her.  
  
Shaking her head, she left the TARDIS, closing the door behind her. The ship hadn't parked itself on the sand, but on the boardwalk of the little village that had cropped up at the edge of the beach. Probably a good thing. The beach itself held too much emotional weight for her to handle right now, if she had to guess.  
  
She moved into the village, lost in thought. Not sure where she was going, or should go.  
  
Well, she _should_ go back to the TARDIS and pretend this never happened.  
  
Couldn't bring herself to do that somehow, though.  
  
She looked up as she turned a corner, and at the end of the block of little houses... there she stood, just that easily. Even from behind, she could immediately recognize her.  
  
She moved toward the familiar figure as if drawn by a magnet, body blatantly ignoring the pleas of her brain to stay the hell away from her. Completely did not listen to it saying that she had to be content with taking all of this in and watching from afar.  
  
Maybe it was stupid. No, it was _definitely_ stupid, but she didn't want to do that anymore. She _shouldn't_ complicate things now. She _shouldn't_ see Rose, but she _wanted_ to see Rose. She wanted nothing more.  
  
Soon enough, she was too close to get away without causing a scene. If she tried to run away now, Rose would hear her.  
  
So, she thought, now she definitely had to commit to it. She steadied her shaky hand, swallowed down the lump in her throat, and reached out to gently touch her shoulder. "Rose Tyler?"  
  
Rose started at the sudden contact, then turned and looked at her full in the face, brow arched. "Yeah?"  
  
Apparently she'd been very confident in the moments leading up to this, but The Doctor hadn't actually been prepared for the flood of emotions that was going to come from seeing Rose again after this long. She gaped at her, and her impressive mind went blank.  
  
She didn't even have time to make up a story about why she knew the woman's name. Somehow, realization was _already_ dawning on Rose's face the instant their eyes made contact. Like some kind of miracle. How could she _tell_?  
  
"...sorry." The Time Lord lost her nerve when she saw that blossoming understanding, and tried to move away, but Rose caught her by the wrist. Her hand was trembling. "Wait."  
  
"I..." She'd started to make up something. She'd started to say it was a mistake, maybe to pass it off and pretend to be some random madwoman walking up to her in the street. She definitely _should_ walk away, but she didn't have it in her. She shouldn't have approached her in the first place, but they were here now. She couldn't _actually_ walk away from this woman right now.  
  
"It's you. It is. Don't you lie to me." Rose pleaded, biting the inside of her lip. "Doctor... Doctor." She whispered, and the sweep of the syllables over her ears broke both of those hearts that were beating way too fast inside her chest.  
  
Again, she pushed past the out she'd been given. She could say she didn't know what Rose was talking about, but no part of her wanted to do that. "What makes you so sure I'm who you think I am?"  
  
"I... I dunno. I just... I _feel_ you. I can feel it's you." Her tone was equal parts 'I know I'm right' and 'Please don't let me be wrong'.  
  
It broke The Doctor down easily, and she sighed. It was a sigh that fell on the fond side rather than sounding put out, though. Rose was so clever. _Always_ so clever. It made her feel nostalgic. Rather than answering, she simply turned her hand so that _she_ was the one grasping _Rose's_ wrist, and lifted the other woman's hand to place it on the left side of her chest. The two heartbeats pulsed in their familiar rhythm, although perhaps a bit fast at the moment. She felt Rose's fingers twitch against her before they closed around the fabric of her shirt.  
  
"Why? _How_?"  
  
The Doctor quieted her with a hand on her arm and a look. "We should go somewhere more private first."  
  
"Yeah... 'course. My house is close."  
  
Next thing The Doctor knew, the two of them were sitting at a table in the tiny kitchen of a house that seemed way too modest for Rose.  
  
Said woman was in the chair across from her, eyes running over every inch of her. Giving her a once over. A twice over, a thrice over. Scrutinizing her up and down.  
  
The Doctor scrutinized _her_, too, in between pushing back the desire to fidget under her intense gaze. That beautiful face was just how she'd remembered it. Almost _too_ exact, actually. "You haven't aged a day, Rose." Her tone was full of awe. It had been several years since they'd seen each other, in Rose's timeline. Damn near a decade, probably. That meant she was well into her 30s by now, chronologically. The point where, in The Doctor's experience, a human would normally start to show _some_ kind of aging. But... she still looked like that young shop girl The Doctor had grabbed by the hand and told to run.  
  
"Yeah. I, erm... I noticed it, too. Expected some quick aging, working with Torchwood. High stress job, right? For a while I thought I just got lucky with my genes, y'know? But time kept going, and it seemed like I... just didn't. I was thinking it might have to do with Bad Wolf."  
  
The Doctor paused. It was very possible. She couldn't say for certain what side effects looking into the heart of the TARDIS, holding the entire Time Vortex, could or couldn't have on a human. She _could_ say what it would do to a Time Lord, of course. Been down that road. But maybe Rose _wasn't_ quite human anymore.  
  
And speaking of not quite human, it suddenly occurred to her that Rose was alone. The house was empty and still.  
  
"Where, er..."  
  
It was obvious what she was trying to ask, despite not quite being able to find the words she wanted to use. Something like 'Where's the bargain bin me I left you with?'. Probably something a little gentler.  
  
But that pretty face went dark, and the message got its way across without words. For an instant it felt like both of The Doctor's hearts had stopped. She never wanted to see Rose wear this expression again. She quickly moved to push the subject along. "When?"  
  
"Couple years ago."  
  
"How?"  
  
Rose laughed. A dry, sardonic type of laugh. "Heart failure."  
  
It made The Doctor's chest hurt. Perhaps a sympathy pain, considering what she'd been told just then. She had to wonder if she'd messed up somehow, making a huge deal out of leaving Rose that 'gift'. Maybe the body really couldn't handle only having one heart. "I'm sorry."  
  
"Don't be. You didn't do anything wrong. Didn't think it would be so soon, but... humans know we have an expiration date, we just never know when it's coming." She smiled, a bit wistfully. "I do miss him. He was like you, but he _wasn't_ like you. The same man, but also not. He was human. He was _so_ human. Spent every single moment he could with me. Loved me with everything he had. I didn't deserve him, really. It didn't matter that it was your face standing in front of me, I could never fully trick myself like you wanted. He wasn't _you_. I loved him, and I cherished the time we had together, but I couldn't love him as much as I loved you. Not even close."  
  
_That_ just made her chest hurt more. "Rose..."  
  
Her companion shook her head. She didn't want more apologies. "And have you been... y'know. On your own?"  
  
"...a little bit, yeah. Most of the time I've kept company. The Ponds, oh. I loved them. They were like family to me. They were with me a long time. For most of the time while I had my first new face. Then Clara. Clara was so brilliant. I miss her. She was with me for a long time too. Through a regeneration, even. We bickered like crazy. Bantered. We even had real fights, but she kept me grounded. Then I had Bill. Nardole. Those two put up with me somehow while I had my last face. Bill liked pretty girls. I would've had to fight her over you." She grinned, breaking into a bit of a laugh when Rose smacked her arm. "Now, I've got my fam. Graham, Ryan, and Yaz. Well, not _right_ now. Dropped them off at home."  
  
She purposely didn't mention River. She didn't think Rose would blame her for having and loving someone else, but River was _gone_, and she wouldn't see her again. Not ever. She'd gone to The Library. It hurt to talk about her, to think about her. That chapter of her life was closed, and she could do nothing about that, not that she was totally sure she'd want to in the face of this.  
  
Honestly... she also found that she felt the same way about River that Rose felt about the Metacrisis Doctor. She had loved River, she genuinely had. But not the same way she loved Rose. And Rose was here, right in front of her. That love that she'd buried underneath a few regenerations was roaring back in force, and she didn't think _River_ would blame her for _that_, either. No, River would want her to be happy.  
  
And she _was_, sitting here across from Rose Tyler for the first time in what felt like eons. There had been a time, a long time, that she'd thought she would never get to see Rose again. She was very glad she'd been wrong about that, however long or short this reunion ended up being.  
  
"The TARDIS brought me here, by itself. I threw my hands up and said 'Take me somewhere'. This is where it carried me. It knows me better than I know myself, sometimes. I've missed you so much, Rose."  
Rose's hand moved to cover hers. "I don't have to tell you I missed you too, do I?"  
  
The Doctor just grinned. "No. But it's nice to hear."  
  
"Oh, get out." Rose laughed, but her eyes sharpened after a moment. She was looking The Doctor over again, gaze lingering at their point of contact. "So... I didn't know you could change your gender."  
  
"I didn't either. Never happened before. Didn't even know it was a thing 'til The Master did it. Became Missy. But, well... every cell in my body changes when I regenerate, so why not?" It hadn't been a big deal to her, really. But she understood why it could be to Rose. Humans placed a lot of importance on things like this for whatever reason.  
  
"You didn't _choose_ it, though?"  
  
"Er... well, no. Not really. I did figure out why I take certain traits in a regeneration... has to do with what I'm thinking about at the time."  
  
Immediately, Rose made the connection. "You're blonde."  
  
"Yes."  
  
Rose gaped at her. "You were thinking about me?"  
  
The Doctor's face had gone so warm she felt like she might explode. She raced to get back to the conversation, and tried to ignore Rose's expression as it turned smug, then melted into fondness. "_Anyway_, choosing faces! Only one I can ever remember actually choosing is the last one. Suppose the past me wanted to send that me a message. To remind me that I'm a good person. That I help people. I, uh... I had a bit of a morality crisis last time. Struggled with whether or not I was a good man."  
  
"You are a good man. Woman. Person." Rose's eyebrows furrowed as she tried to work this out. The Doctor couldn't help finding it adorable. "Bloody hell, which is it?"  
  
"It doesn't matter, I think. I know what you mean either way." Curiosity had grabbed her, though. Clearly Rose had some kind of interest in her change of gender. She couldn't quite tell if that was indication of something positive. "So, Rose... it's, uh... it's alright, yeah? Doesn't _bother_ you that I'm..." The Doctor fumbled for her words.  
  
"Thick?"  
  
"...huh?"  
  
"Thick." She repeated, sitting back in the seat and crossing her arms. "I mean, you must be, to think I'd stop loving you over being a girl."  
  
The Doctor stared. It wasn't the reaction she'd been expecting. "I just, uh... I thought it might be a bit different. Y'know, when it wasn't just my face that changed."  
  
"I already loved you before your face changed the _first_ time. Yeah, it freaked me out at first when it happened, but that's probably _why_ I was so freaked out. I loved you and I thought you were gone. I didn't know any better. I mean, humans only have one life. We can't go 'poof' and change our faces and suddenly we're alright. It's always been _you_ I love, your soul. Didn't love you for your... bits. Or your handsome face. Although that _second_ face you had was definitely my favorite after I got used to it." Rose grinned, poking her tongue through her teeth in that endearing way she always did while nudging The Doctor in the side. "This one's good too. You're cute as a girl."  
  
The Time Lord playfully batted the assaulting limb away. "I about half wonder what you would've said about the other ones."  
  
Rose looked at her with an expression that was a cross between wonder and distaste. She'd previously understood that The Doctor only regenerated if death was imminent. How much danger had she been in since they were together? "How many times have you changed since then?"  
  
"This was the third time. Stayed a handsome young guy for the first one. Went a bit kooky, though. Well, more than normal, I mean. Lost my eyebrows and picked up an obsession with bowties. That was... actually supposed to be the last one I had left in me. Time Lords can't regenerate infinitely, just twelve times. I spent about 600 years fighting a crazy battle in a place called Trenzalore. I was old, and hurt, and I was going to die. _Actually_ die, like the permanent kind. And I was scared. It was Clara... bless her. _Somehow_ she convinced the Time Lords to let me have another go 'round. They gave me a new regeneration cycle. Not sure how many tries I've got at it this time. Could be twelve. Could be more. Not that I'm too keen on finding out, mind."  
  
The true gravity of things hit Rose. So much had happened since they parted ways. It had only been a handful of years for her, but The Doctor had lived nearly a thousand in that same period. Suddenly a few regenerations didn't seem so unreasonable.  
  
"Turned old and crotchety for the one before this. The first new one, and that's what I ended up doing. Went way overboard with the eyebrows to compensate and told the ties to piss off altogether. Think you might've liked me last time too. I had a tendency to be sassy, almost like when you first met me. Kept his accent for this one, too."  
  
Rose leaned forward again and poked her in the hand. "You can't give me the 'lots of planets have a North' line this time. You're _definitely_ Scottish."  
  
The Doctor rumbled with laughter. "Guilty! It'd be Amy's fault. Pond. She was lovely. Very feisty, _very_ Scottish. I think the two of you would've gotten on well. She told me never to be alone, too." A shadow crossed her face, just a flicker. Brief enough that most people wouldn't notice it. But Rose wasn't most people. She didn't ask what happened, though. If The Doctor wanted to tell her, she would tell her. But she wouldn't make her.  
  
No, rather than that, she gently and quietly took her hand. Squeezed it. Let her know she was there.  
  
That little gesture just _screamed_ love. The echo was loud in the small room.  
  
The Doctor swallowed sharply and grasped at a change of subject. "So, er... Bad Wolf Bay, huh? You live here now?"  
  
"Yeah. Moved here a couple years ago."  
  
It didn't escape The Doctor's notice that 'a couple years ago' had also been when the Metacrisis Doctor had died.  
  
"Not having any trouble with the bit about it being in Norway?"  
  
"I get by with English. I've learned a bit of Norwegian, too. It's not that hard, really."  
  
"It wouldn't be when you're this brilliant, would it." She hadn't meant to say it aloud, but decided to roll with it. She smiled at Rose, tucking a wandering strand of hair behind her ear.  
  
"Seriously, get out." The other woman laughed, giving that tongue touched grin again. Very briefly, though. Her eyes soon turned sad. Afraid, maybe. "How long have you got, this time?"  
  
The Doctor felt like her breath had been knocked out of her. She didn't want to see Rose looking like this. She felt guilty, because the reason was very obvious. "Dunno. I wasn't set a time limit, necessarily." 'I'm not burning up a sun this time', she added in her head.  
  
"Maybe, but... we don't know exactly _how_ you got here, right? What if whatever gap you came through closes up again? The other universe needs you. You can't get stuck here with me." The 'much as I'd like that' was obvious in her tone. As was the 'you've got to go back before I start feeling selfish'.  
  
She knew Rose was right, of course. Rose was always right. She'd learned so much from The Doctor. Well, they'd learned so much from each other, really.  
  
This time her cleverness _hurt_.  
  
"Had enough of me already, have you?" She teased, maneuvering her hand so she could pat Rose's.  
  
"Never." There was as much pain in that word as there was acceptance. Rose Tyler had learned that the world, the universe, was so much bigger than her. Clearly that didn't make something like this any easier to handle.  
  
The Doctor admired this woman so much in this moment for her self restraint and care for others. It knocked the breath out of her again. If she were in Rose's shoes, she didn't know that she could've done the same. Be given exactly what she wanted... and then give it up again, just like that, for the sake of others.  
  
It was a moment like this that reminded her _how much_ she loved Rose, too.  
  
"Walk me home?" She asked, fingers curling around her companion's hand.  
  
"Like I'd let you go alone."  
  
They left the house again, walking hand in hand down the boardwalk toward the TARDIS. The corner where it was parked wasn't far from Rose's house, ironically. It occurred to The Doctor that she'd taken up residence close to the beach. Probably on purpose. No, _definitely_ on purpose.  
  
It squeezed both of her hearts.  
  
Rose walked her up to the door, and they just stood there a while, in silence. The only sound around them was the waves gently crashing against the shore. Each of them had their own distinct feeling of being here before.  
  
Probably because they _had_.  
  
The tension in the air was palpable.  
  
"Right. Well, probably time to get a move on." The Doctor turned toward her Box, letting go of Rose's hand, and smiled to herself as she reached toward the door handle.  
  
She then turned back to Rose, suddenly, in a way that was supposed to telegraph that she'd forgotten to say something. She held her breath as she looked into those brown eyes. Eyes that she'd dreamt of damn near every time she'd slept for what felt like centuries. And then it dawned on her. For her, it _had_ been centuries.  
  
She broke, and her carefully constructed act was finished with six little words:  
  
"Be needing this back, I think."  
  
From her jacket pocket, she produced a very familiar looking key, and held it up to Rose. The chain was well worn, and slightly rusted around the edges.  
  
Rose's heart leapt as she laid eyes on that old key, and her eyes welled up immediately. Her hand closed around The Doctor's again, holding the key between their palms, and she leaned forward, backing her up against the TARDIS door, and kissed her.  
  
It was a kiss The Doctor felt like she had waited several lifetimes for, because she sort of _had_. Her hand found its way to the back of Rose's head, pulling her in closer. She wanted, _needed_ Rose as close as she could possibly get her. The weight of her long lost companion's body pressed up against hers, pinning her to the door, grounded her, keeping her aware of reality. It was so unbelievable, how much she had missed her.  
  
Rose broke the kiss first, moving her head to rest it in the crook of The Doctor's neck as she started to outright sob into her. "Yes. God, yes." She choked, an answer to an unasked question. She would go. Nothing would _keep her_ from going. There was nowhere she wanted to be more than right here, by her Doctor's side.  
  
The Doctor looked at her a while. Held her. Reminded herself a few more times that this was real and not some kind of hallucination. It wouldn't have been the first time. Rose looked up at her again, once her crying had calmed down slightly, and she was beautiful; snotty nose, makeup smears, and all. Those watery eyes showed someone that was still _so_ in love, and it made both of her hearts swell. She only hoped her own eyes told Rose the same.  
  
But then she stopped herself in her tracks.  
  
No, she _wasn't_ going to do this again. She _wasn't_ going to continue to play this game of half measures and 'almosts'.  
  
She wasn't going to keep Rose's heart hanging on a string until the last bloody moment. If there was one thing she could say she was _furious_ at that version of herself for, it was that.  
  
"Rose Tyler, I love you." She said, confidently, and gave the other a tight squeeze when she began to bawl again.  
  
Frankly, it had been a massive cock-up not telling her the first time, or even _trying to_ until it was too late. It had been something she'd wanted to hear for... who knew how long.  
  
"I love_ you,_ Doctor. Still, still, still." She told her, tone desperate to get that message across, clinging on for dear life as if she thought she might disappear again.  
  
The Doctor let her be. Let her stay like that. Let her cling. She understood all too well what Rose was feeling right now.  
  
She'd felt the ghost of the same thing every single morning she'd woken up from dreaming of her.  
  
After a while, a fond hand stroked into the small of Rose's back, calming her. She relaxed her death grip slightly and her gaze went upwards again. "Quite right, too." The Time Lord smiled through her own tears, looking absolutely besotted now, and reached behind her to push the TARDIS door open. She pulled her hand from Rose's, finally, leaving the key behind. "C'mon." She said with a sniffle, wiping her cheeks and disappearing into her Box still wearing that smile.  
  
Rose lingered, just a moment, letting the emotion run its course. Her free hand laid itself upon the wood, and she looked at it with all the reverence in the world. She'd made so many memories since the first time she'd laid eyes on this seemingly unassuming blue box. Happy memories, painful memories.  
  
The happiness had always been worth the pain, though. And it always would be.  
  
She smiled, clutching that key tightly in her hand, and went inside, once again crossing the threshold into the home of that one being she loved more than anything else in the entire universe.  
  
Finally, she felt like she was home again too.

**Author's Note:**

> I'm really not gonna lie, pouring this one out was a nice little mental break from all the angst I've been writing in my currently running Good Omens fic... this is also pretty much the first pure fluff fic I've written, uh, ever. I.E. no explicit content AT ALL, just feels. So there's also that. Let me know what you think about it! Come talk to me on [tumblr](https://cocolinears.tumblr.com/) if you like, too! The content I post/reblog there is mostly Good Omens stuff but it's not necessarily exclusive to that!


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